Detecting method of impurity concentration in crystal, method for producing single crystal and apparatus for the pull-up of a single crystal

Abstract

A temperature sensor 42 is provided in a furnace 11, measuring temperature above a molten liquid 24 put in a crucible 12 to check proceedings of evaporation of oxygen vaporized from a free surface 44 of the molten liquid 24. From the data, and considering the relation with the oxygen dissolved into the crucible 12, the oxygen concentration in the molten liquid 24 can be found and the amount of oxygen taken into a single silicon crystal 40 pulled up from the molten liquid 24 can be figured out.

What is claimed is: 
     
       1. An apparatus to pull up a single crystal which is pulled up from a molten liquid in a crucible placed in a furnace while growing, said pulling up apparatus for a single crystal comprising: a valve controlling inside pressure of said furnace;   a heater heating said molten liquid;   a driving motor rotating said crucible;   a pull up unit pulling up while rotating said crystal;   an evaporation detector arranged in said furnace and detecting at least any one of the amount of evaporation of impurity from said crucible, the temperature above said molten liquid, or the pressure inside of said furnace; and   a controller to shift at least any one of the opening angles of said valve, the heating value of said heater, the rotational speed of said drive motor, the rotational speed or pull-up speed of the pulling up unit, according to the detection signal of the evaporation detector.   
     
     
       2. An apparatus to pull up a single crystal which is pulled up from a molten liquid in a crucible placed in a furnace while growing, said pulling up apparatus for a single crystal comprising: a valve controlling inside pressure of said furnace;   a heater heating said molten liquid;   a driving unit to vertically move up and down said crucible while rotating the crucible;   a pulling up unit to pull up said crystal while rotating the crystal;   a magnetic field generator to apply a magnetic field to said molten liquid;   an evaporation detector arranged in said furnace and detecting at least any one of the amount of evaporation of impurity from said crucible, the temperature above said molten liquid, or the pressure inside of said furnace; and   a controller to control at least any one of the opening angles of said valve, the heating value of said heater, the rotational speed of said drive motor, the rotational speed or pull-up speed of the pulling up unit, or the pattern or strength of the magnetic field generated by said magnetic field generator, according to the detection signal of the evaporation detector.